The project is for the central building of a community center used by the communities of Blacksburg and Christiansburg. The building is a space configured as a hub that uses axes to determine entering, exiting and vertical movement. The hub configuration of the building is in concentric rings around the atrium in both space and materials. As materials were brought into the building, they enhanced the strong axial configuration and emphasized the layers surrounding the central hub space of the atrium. There are two pairs of axes in the building. The entrance axes are perpendicular to the faces of the building and provide lines of sight through it. They also establish the paths of entering and exiting the building. The diagonal axes regulate the vertical movement throughout the building. / Master of Architecture

No / The purpose of this study was to ascertain whether or not spreading depression (CSD) propagates symmetrically along the anteroposterior axis of the cortex of mice, and to determine where CSD should be elicited to achieve a uniform exposure of the cortex to this phenomenon. Experiments were performed in halothane-anesthetized mice, with three different locations aligned 1.5 mm from the midline used for either KCl elicitation of CSD or the recording of its propagation. Our results demonstrated that, at least in the mouse cortex, CSD propagated much more effectively from posterior to anterior regions than in the opposite direction. This feature was due to a different efficacy of propagation in the two opposite directions, and not to a reduced susceptibility of occipital regions to CSD elicitation. Heterogeneous CSD propagation constitutes a potential pitfall for neurochemical studies of post-CSD changes in mice, as brain tissue samples collected for this purpose should be uniformly exposed to CSD. Occipital sites for CSD induction are clearly optimal for this purpose. If CSD propagation is confirmed to be more effective from posterior to anterior regions in other species, this may be relevant to the pathophysiology of classical migraine because the most frequent aura symptoms (i.e., visual disturbances) originate in the occipital cortex.

Research on adolescent drinking shows that younger people are at greater risk of developing behavioral deficiencies that can be detrimental to their social relationships and health over time. Recent research has shown that changes within the microbiome-gut-brain axis (MGB) can affect social behavior. These changes involve microbiota populations that influence addictive behaviors after prolonged substance intake through neurochemical shifts that extend through the nervous, circulatory, and immune system. Using Massey's biosocial model, I aim to expand on the relationship between the MGB axis, social behavior, and adolescent alcohol use disorder through a meta-theoretical approach. I explore the strengths and shortcomings of Massey's biosocial model of segregation and stratification and its use of the allostatic load model, telomere length, and gene exposure to develop a stronger theoretical concept using the micro-gut-brain axis as a conceptual foundation. Can the MGB-axis model be used to identify potential pathways in which alcohol use disorder (AUD) persists from adolescence to adulthood? I find that adolescent drinking leads to changes in microbiota populations that are known to influence AUDs and increases the development of diseases such as liver disease and its effects on social behavior. The MGB axis can help us understand the effects of substance and dietary habits on disease and illness by connecting life science knowledge and sociological perspectives. With this modern application of cognitive sociology, I have shown that future research on addictive behaviors should consider the application of biomarker data to further expand on new theoretical and methodological approaches in the study of disease and addiction.

The competitive nature of the modern manufacturing industry coupled with increasing consumer demand and a dynamic economy, lead manufacturers to operate their production computer numerical control (CNC) machines beyond their capable operational limits. This unsustainable behaviour leads to the rapid deterioration and breakdown of the CNC’s critical subsystems and components. Consequently, increasing the amount of unplanned downtime and cost of maintenance. To put it into perspective, downtime in the automotive manufacturing sector can reach upwards of USD 2 million per hour. The linear axis is one of the CNC’s critical subsystems, its robust and accurate positioning capabilities drive the operational and geometric performance of CNC machines. Failure to promptly address developed faults in the linear axis, may lead to poor geometric performance and system sluggishness, overall affecting the production quality of manufactured products. Therefore, it is crucial to monitor the health condition of this subsystem and its components. The principal aim of the presented research was to develop a condition-based monitoring (CBM) system to monitor the health condition of the linear axis and its various components. To achieve this aim, the research work was divided into four objectives. Firstly, objective one consisted of designing an industrial level linear axis testbed that resembles a CNCs linear axis to conduct all experiments. Furthermore, the testbed’s main contribution is to serve as a data generation platform for the research community. Objective two focused in the design of a framework to establish a reference baseline dataset for CBM systems. The framework’s contribution consisted of building an understanding of the healthy condition of the linear axis and its components using vibration monitoring and time domain statistical feature analysis. It was found that under a known healthy condition the time domain features exhibit low variability, there is a negligible difference between a forward and reverse stroke, and a robust baseline can be established by collecting data for approximately an hour of operation rather than a 6-hour operational shift. The third objective of the research consisted in conducting a comprehensive health assessment of the linear axis and its components through a multi-sensor approach, when a root-cause failure fault (FF) is present. Additionally, the health assessment’s contribution was further enhanced by analyzing the repair condition of these faults and comparing the results to the original baseline. The assessment demonstrated that the most frequently occurring root-cause FF, carrier block raceway blockage, can easily be detected through the system’s internal data. Moreover, the repair state condition exhibited less than 10% error when compared to the baseline state. Finally, the fourth objective was centered in the development and application of a novel signal segmentation technique to detect and localize the leading root-cause of failure in the linear axis, misalignment. The technique’s main contribution rests in its functionality as a localization and verification tool in linear axis maintenance. The findings from the conducted studies revealed that the technique increased the usability of time domain features such as RMS, by approximately double. Lastly, the evaluation of both stroke directions aided in localizing the misalignment in the linear axis. / Thesis / Doctor of Philosophy (PhD) / Computer numerical control (CNC) machines are pivotal assets for the manufacturing sector, yet the demand from the modern industry often drives the operation of these machines to exceed their capable operational limits. Consequently, causing the breakdowns of their critical subsystems, resulting in high maintenance costs and machine downtime. The linear axis is one of these critical subsystems, primarily tasked with the positioning function in the CNC machine. In the presented research, a condition-based monitoring (CBM) system was developed, to monitor the health state of this critical subsystem and its components. The development of the system first focused on understanding the healthy condition of a linear axis and its components by implementing a statistics-based baseline dataset framework. Then, a comprehensive health assessment was conducted to evaluate multiple data streams and detect signal variation when root cause failure faults (FFs) are present in the system. Unlike previous health assessments, the repair condition of the evaluated components was also included in the analysis. Finally, a novel signal segmentation algorithm was developed to complement the CBM system, specifically serving as a localization tool to pinpoint an artificially induced misalignment on the guide rail component of the linear axis.

A avaliação do ventrículo esquerdo (VE) é uma das principais contribuições da ecocardiografia no estudo da função cardíaca e inclui a mensuração dos diâmetros da cavidade e espessura das paredes em diástole e sístole. O estudo por meio do modo M tem sido usado como padrão para a realização da mensuração e para o cálculo de índices sistólicos, mas o modo bidimensional também é utilizado para este fim. As medidas podem ser adquiridas a partir de dois planos de imagem: transversal e longitudinal. A definição de intervalos de confiança para valores normais de VE permite a identificação de remodelamento ventricular, concêntrico ou excêntrico, decorrente de doenças cardiovasculares ou sistêmicas. Assim sendo, o objetivo deste estudo foi comparar as medidas ecocardiográficas desta câmara obtidas pelos seguintes métodos: modo M em corte transversal, modo M em corte longitudinal, modo bidimensional em corte transversal e modo bidimensional em corte longitudinal. Adicionalmente, estudou-se o comportamento do efeito do peso e do sexo nos métodos mencionados. Foram selecionados 40 cães adultos da raça Pastor Alemão sem alterações cardiovasculares. A realização do ecocardiograma de cada animal inclui os quatro métodos descritos acima, de acordo com o recomendado pela literatura. Foram pesquisados os efeitos do corte e do método, bem como a influência do peso e do sexo, sobre cada medida estudada, linear ou derivada. O peso apresentou correlação com todas as medidas lineares de VE em pelo menos um dos métodos, mas não com fração de encurtamento (FE) e fração de ejeção (FEj). Utilizando-se a análise univariada, verificou-se que machos apresentaram todas as medidas estudadas significativamente maiores que fêmeas em pelo menos um dos métodos, exceto FE e FEj, cujos valores não foram diferentes entre os sexos. Observou-se efeito isolado do corte apenas sobre diâmetro diastólico final do ventrículo esquerdo (DdFVE), com medidas maiores obtidas no corte transversal, e mudança de comportamento do sexo nos cortes com influência significativa do peso sobre septo interventricular em diástole (SIVd). Houve efeito isolado do modo sobre os índices de função sistólica FE e FEj, com valores maiores fornecidos pelo modo M. O peso teve efeito isolado positivo sobre parede livre de ventrículo esquerdo em diástole (PLVEd), exceto no modo M em corte transversal e (diâmetro sistólico final de ventrículo esquerdo (DsFVE). O sexo, retirada a influência do peso, teve efeito isolado apenas sobre DdFVE, com machos apresentando valores significativamente maiores que fêmeas em ambos os cortes no modo bidimensional. Os resultados Os resultados mostram que há risco de erro de interpretação quando valores normais de referência, gerados a partir de determinado método, são utilizados para a avaliação de um paciente examinado por técnica de mensuração diversa, especialmente quando se obtém resultados nos limites superior ou inferior de normalidade. / Left ventricle (LV) evaluation is one of the most important contributions of echocardiography in the assessment of cardiac function. It includes measurements of internal diameter and wall thickness at end-diastole and end-sistole of this chamber. M Mode echocardiography has been widely used for measuring linear dimensions and quantifying systolic function, but bidimensional mode is also used with the same purpose. The LV measurement can be derived from transverse or longitudinal images of the heart. The establishment of normal confidence intervals of LV dimensions allows identification of concentric or excentric ventricular remodeling process secondary to cardiovascular and systemic diseases. The aim of this study was to compare LV measurements obtained from four methods: M mode in short-axis, M mode in long-axis, bidimensional mode in short-axis and bidimensional mode in long-axis view of the heart. In addition the effect of weight and gender over measures was studied in the methods mentioned above. Forty adult German Shepherds without cardiovascular diseases were selected. The echocardiogram of each animal included the four described methods, according previous referenced recommendations. The effects of axis and mode as well as weight and gender were studied for each linear or derived LV measure. Weight correlated with all linear LV measures at least in one method, but not with ejection fraction (EF) and shortening fraction (SF). All LV measures of males were greater than those of females at least in one method, except for EF and SF, which did not differ between sexes. Isolated effect of the axis was observed only for LV end diastolic diameter (LVEDD), with greater values obtained from short-axis views. The combined effect of axis, gender and weight was identified in interventricular septal end diastolic thickness. There was isolated effect of mode over EF and SF, with greater measures derived from bidimensional mode methods. Weight had isolated significant positive effect over LV enddiastole posterior wall thickness in all methods, except from M mode performed in short axis, and LV end-sistolic diameter. Gender had isolated effect only over LVEDD, males showing greater values than females in bidimensional mode in short and long axis. Professionals should be aware of the possibility of erroneous interpretation when using data obtained by a different method of that used in the patient exam as reference, mainly for the values situated in inferior and superior limits of confidence intervals.

Cette étude porte sur la représentation de la déformation du corps humain, afin de défendre l’idée que ces exemples de corps déformés ont fini par engendrer de nouvelles recherches et des transgressions artistiques qui caractérisent le XIXe siècle français. Les œuvres de Hugo et de Ingres ont été choisies en raison de la richesse symbolique qu'y acquiert la déformation du corps humain, au confluent de plusieurs traditions mythologiques. Pour l’étude des corps déformés et de leur rôle dans la cosmogonie hugolienne, nous nous servirons d’une cosmogonie analogue : celle de Dante Alighieri qui a pu nourrir l’imaginaire hugolien auquel nous ajoutons le labyrinthe existentiel. Méthodologiquement, cette analyse sera faite à partir de la lecture de l’espace proposée par Greimas. Les axes orthogonaux y sont marqués par les personnages en établissant des emplacements spécifiques qui indiquent un langage à déchiffrer. Dans l’œuvre d’Ingres, notre but sera de mettre en relief la déformation du corps en tant que travail esthétique pour la révélation de la beauté plastique. La déformation anatomique caractérise déjà ses premiers personnages masculins et marque davantage ses figures féminines que nous étudierons plus en détail. Pour affiner cette démarche nous avons établi certaines relations avec d’autres peintres tels que son maître David, ou bien avec des sculpteurs comme son ami Lorenzo Bartolini, James Pradier et des écrivains comme Théophile Gautier et Hugo. Cette recherche s’appuiera sur plusieurs supports théoriques, indispensables pour s’orienter dans cet univers riche de références à l’Antique, au mythologique, au religieux, au sacré, au politique, au social, à l’artistique, au fantastique et au fantasmagorique. C’est pourquoi Phidias, Vitruve, Jean-Jacques Rousseau, Jorge Luis Borges, Mircea Eliade, Claude Lévi-Strauss, Michel Foucault, Umberto Eco entre autres sont évoqués pour aider à la compréhension de notre étude. / This study focuses on the representation of the deformation of the human body, arguing that these examples of physical deformity have eventually engendered new research and artistic transgressions that characterise nineteenth century France.The works of Hugo and Ingres are focused upon on account of the symbolic richness derived from them with regard to the deformation of the human body, and the confluence of several mythological traditions. For the study of deformed bodies and their role in Hugo's cosmogony, we will use a similar analogous cosmogony: that of Dante Alighieri, which was able to feed the Hugolian imagination and to which we add the existential labyrinth. Methodologically, this analysis will be made by reading the space proposed by Greimas. Orthogonal axes are marked by characters in establishing specific locations that indicate a language to decipher. Regarding the work of Ingres, our goal is to highlight the deformation of the body as a work of aesthetics for the revelation of plastic beauty. Anatomical deformation already characterises his first masculine characters and mark still further his female figures which we have studied in more detail. To refine this approach we have established some relationships with other painters such as David, Ingres' Master, and with his friends the sculptors Lorenzo Bartolini, James Pradier and also with writers such as Théophile Gautier and Hugo. This research is based on several theoretical sources, they are essential to orient this rich universe of references to the Antique, the mythological, the religious, the sacred, the political, the social, the arts, and fantasy. This is why Phidias, Vitruvius, Jean-Jacques Rousseau, Jorge Luis Borges, Mircea Eliade, Lévi-Strauss, Michel Foucault, Umberto Eco among others are also discussed to help the understanding of our study.

Cortisol, the principal glucocorticoid secreted from the adrenal glands, is essential for life. Healthy cortisol levels are maintained through negative feedback on the central nervous system (CNS) – pituitary stimulatory apparatus which regulates production of adrenocorticotropin (ACTH) and contains a light–entrained intrinsic CNS driven diurnal rhythm. Cortisol participates in a regulatory mechanism where inflammatory cytokines stimulate cortisol release and cortisol in turn suppresses cytokine release. The effects of cortisol in inflammatory states include elevating blood pressure and metabolic regulation. This thesis contains three exploratory studies examining circulating cortisolaemia using the best available methodologies (total and free cortisol and corticosteroid-binding globulin (CBG)) in clinical states characterized by immune activation/ inflammation and altered blood pressure. These clinical states include: (1) septic shock, (2) hypertensive disorders of pregnancy and (3) obesity-induced hypertension. Prior to the studies described here, little was know about cortisolaemia in these common pathological states. Septic shock is a life threatening condition that complicates severe infection and is characterized by systemic inflammation and refractory hypotension. High plasma total cortisol levels and attenuated responses to synthetic ACTH stimulation are associated with increased mortality. The use of corticosteroids in septic shock has been highly controversial for decades, however recent trials have reported haemodynamic and survival benefits associated with the use of physiologic steroid replacement in patients with relative adrenal insufficiency (RAI) – currently defined as a total cortisol increment of 248 nmol/L or less following ACTH (250 μg) stimulation. However, CBG and albumin levels fall by around 50% with an increase in plasma free cortisol in critical illness. Hence, total cortisol may not reflect the biologically active free (unbound) cortisol, suggesting that standard assays for plasma cortisol (which measure total plasma cortisol) underestimate HPA axis activity. In this study, we have showed that plasma free cortisol is a better guide to circulating glucocorticoid activity in systemic infection than total cortisol. We have also validated the use of Coolens’ method in estimating free cortisol in systemic infection, using plasma total cortisol and CBG measurements as plasma free cortisol is not performed in clinical laboratories. Free cortisol measurement allows better categorization of RAI and non-RAI groups with a free cortisol increment of 110 nmol/L as cut-off. Moreover, we have shown that survivors of RAI have normal adrenocortical function on follow-up testing suggesting a lack of functional adrenal reserve rather than adrenal damage during critical illness. Larger randomized controlled trials will be required to redefine RAI using free cortisol measurements and relate that to clinical outcomes and responses to corticosteroid therapy. Nitric oxide (NO) is normally produced in the endothelium by the constitutive form of the NO synthase and this physiologic production is important for blood pressure regulation and blood flow distribution. Studies have shown that an overproduction of NO by the inducible form of NO synthase (iNOS) may contribute to the hypotension, cardiodepression and vascular hyporeactivity in septic shock. Clinical studies of non-selective inhibitors of the L-arginine nitric oxide pathway showed increased mortality from cardiovascular complications. However, glucocorticoids, which improve vasopressor sensitivity, may act by partially suppressing NO synthesis through selective direct inhibition of iNOS, and suppression of inflammatory cytokine synthesis. Hence, plasma nitrate/ nitrite (NOx) levels may provide a titratable end point to individualize glucocorticoid therapy in sepsis. The NOx study in this thesis showed that cortisol (total and free), CBG and NOx correlated to illness severity. Free cortisol, and to a lesser extent total cortisol, but not NOx levels, predicted septic shock. NOx levels were characteristically stable within individuals but inter-individual differences were only partly accounted for by illness severity or renal dysfunction. NOx levels correlated weakly with cortisol, did not relate to the need for vasopressors and were not suppressed by hydrocortisone treatment. Thus, NOx is not a suitable target for glucocorticoid therapy in septic shock. Pregnancy is the only sustained physiologic state of hypercortisolism in humans. A large body of data suggests that excessive foetal and prenatal glucocorticoid exposure leads to reduced birth weight and adverse health in offspring such as elevated blood pressure and insulin resistance. Pre-eclampsia and gamete donor pregnancies are associated with immune activation, elevated inflammatory cytokines as well as elevated blood pressure. Prior to the study described in this thesis however, there was no prospective data on maternal cortisolaemia in these complicated pregnancies. My study has demonstrated for the first time that there was a substantial fall in plasma CBG levels in the last few weeks of gestation with a corresponding rise in free cortisol in normal pregnancy, a finding obscured for methodological reasons in past studies. This free cortisol elevation in late pregnancy may facilitate organ maturation in the foetus and perhaps prepare the mother for the metabolic demands of labour. In pre-eclampsia and gestational hypertension, plasma CBG, total and free cortisol levels were lower in late third trimester; and in IUGR, plasma CBG levels were suppressed from 28 weeks gestation until delivery but with no significant difference in plasma total and free cortisol. Women with assisted reproduction using donor gametes/ embryos had significantly lower plasma CBG, total and free cortisol levels even in those with normal pregnancy outcomes. Low CBG may be due to reduced synthesis or enhanced inflammation-driven degradation. Low maternal cortisol may be due to a lack of placental corticotropin-releasing hormone, or reduced maternal ACTH, driving cortisol production. This unanticipated maternal hypocortisolism in complicated pregnancies may trigger precocious activation of the foetal HPA axis and could have implications for postnatal and adult health. Speculatively, since excess prenatal GCs increase HPA axis activity, we proposed that maternal hypocortisolism may predispose to the hypocortisolaemic state characterized by fatigue, pain and stress sensitivity, in offspring. The third state of immune/ inflammatory activation associated with blood pressure dysregulation studied in this thesis is obesity. The epidemiologic relationship between obesity and hypertension is widely recognised. Central obesity in particular has been associated with exaggerated HPA responses to stimuli. Studies of severe dieting and starvation resulted in hypercortisolism and a significant decrease in CBG. The HPA axis and the renin-angiotensin-aldosterone system (RAAS) have been implicated in the pathophysiology of obesity-induced hypertension. However, there is little data on the effect of moderate weight loss (30% caloric restriction) on adrenocortical function, and the relation of adrenal hormones to altered blood pressure with weight loss. In this study, measures of HPA axis and RAAS and blood pressure monitoring were performed in twenty-five obese subjects before and after a 12-week diet program (6000kJ/day). Short-term, moderate weight loss (mean 8.5 kg) was associated with a small reduction in blood pressure (mean arterial pressure 6 mmHg) and significantly reduced levels of aldosterone and renin but not cortisol levels. These findings suggest that aldosterone may have an important role in the blood pressure reduction with weight loss via a renin mediated mechanism, perhaps involving renal sympathetic tone. In contrast to severe caloric restriction, HPA axis activation does not occur with moderate weight loss. This suggests a threshold effect of weight loss on the HPA axis where greater caloric restriction is required for HPA stimulation, or a counterbalancing of central and direct adrenal effects on HPA axis function. Overall, these three exploratory studies have provided novel data on HPA axis function in systemic infection, pregnancy and in diet-induced weight loss. Each study offers a basis for further studies of HPA axis function in these disorders. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1289330 / Thesis(Ph.D.)-- School of Medicine, 2007.

The aquatic environment is severely impacted by xenobiotics that are released due to anthropogenic activities, threatening ecosystem health. Some of these contaminants accumulate in lipophilic fish tissues and are maternally transferred to developing offspring, affecting their growth and performance. However, knowledge about the long-term and generational impacts associated with maternal transfer of contaminants is limited in fish. In this thesis, the hypothesis tested was that maternal transfer of bisphenol A (BPA) leads to disruption in the developmental programing of growth and stress axes functioning in rainbow trout (Oncorhynchus mykiss), and that these changes are passed on to the next generation. This was tested by exposing oocytes to either control (vehicle; <0.01% ethanol) 0.3, 3.0, and 30.0 mg l-1 BPA in ovarian fluid for 3 h, prior to fertilization, to mimic maternal transfer. This led to the accumulation of 0, 0.8, 4.4 and 41.3 ng BPA embryo-1. Oocytes were fertilized with milt from clean males, and offspring growth, development and stress performances were assessed in a clean environment for a year (F1 generation). For F2 generation, oocytes collected from F1 females, raised from the different BPA accumulated eggs, were fertilized with milt from clean males and raised in a clean environment for one year as described for F1 generation. The accumulated BPA in eggs was quickly cleared and it was no longer detected in the F1 embryos at hatch. BPA exposure reduced specific growth rate and increased food conversion ratio in larvae reared from BPA-laden oocytes. Moreover, BPA-exposed fish had an altered cortisol developmental profile and a delay in stress axis maturation. In addition, the mRNA abundance of genes involved in somatotropic [insulin-like growth factor (IGF) -1; IGF-2; IGF receptor b (IGF-1rb)] and stress axes functioning [steroidogenic acute regulatory protein (StAR); cytochrome P450 side chain cleavage (P450scc)] were altered. Also, changes in thyroid signaling [thyroid receptor (TR) mRNA levels] and cortisol signaling [glucocorticoid receptor (GR) protein expression] were disrupted temporally during development. These results demonstrate that BPA accumulation in eggs, mimicking maternal transfer, impacts growth and development, and delays stress axis maturation via non-reproductive endocrine disrupting routes in trout. Some of the BPA changes seen in F1 generation also persisted in the F2 generation. For instance, ancestral exposure to BPA led to reduced growth and whole body glycogen content prior to feeding in the F2 fish. The developmental transcript profile of growth hormone-1and -2, IGF-1 and -2 and IGF-1rb, along with whole body cortisol levels were impacted by ancestral exposure to BPA. Moreover, a delay in cortisol dynamics post-stress was noted in the F2 fish of BPA exposure lineage. Our results show that ancestral exposure to BPA leads to effects on growth and stress performance in rainbow trout, but the mechanism is not known. To further investigate the long-term effect of BPA accumulation in eggs on stress performances, F1 and F2 juvenile fish were subjected to an acute stressor. Also, head kidney tissues from these juvenile fish were subjected to adrenocorticotrophic hormone (ACTH) stimulation in vitro to assess cortisol production capacity. BPA accumulation in eggs led to a reduced acute handling stressor-induced plasma cortisol response in trout from the F1 and F2 (only high BPA group) generations. Also, BPA exposure had a pronounced impact on acute handling stressor-mediated plasma glucose (only F2 generation) and lactate levels, indicative of a metabolic disturbance. BPA exposure (only the 4.4 ng group) did affect unstimulated but not stimulated [ACTH or 8-bromo-cyclic AMP (8-B-cAMP)] cortisol production from head kidney slices of juvenile fish from F1 generation. In the F2 generation, there was an increase in ACTH-stimulated cortisol production only from the high BPA-exposed group. Overall, BPA in eggs disrupts long-term cortisol and metabolic stress performances in rainbow trout. While the impaired plasma cortisol stress performance was dose-related in the F1, the effect was apparent only for high BPA group in the F2 generation, suggesting that the generational effects on cortisol stress axis functioning may be concentration-dependent. A metabolomics approach further confirmed multigenerational effects associated with BPA accumulation in eggs. Analysis of the metabolome profile at hatch and prior to first feed, using gas chromatography-time of flight-mass spectrometry (GC-TOF-MS), revealed a BPA-mediated metabolic disruption, including changes in pathways involved in carbohydrate, lipid and amino sugar metabolism, and amino acid metabolism and synthesis. Pathways involved in citric acid cycle and alanine, aspartate and glutamate metabolism were altered in both generations, suggesting that these pathways have the potential to be markers with predictive value for multigenerational effects of BPA in fish. Altogether, the study provides novel insights on the impact of BPA on rainbow trout metabolome at hatch and first feed. The results suggest that pathways involved in energy metabolism are targets for BPA impact and should be investigated as potential markers for BPA toxicity. Overall, BPA accumulation in oocytes induces long-term delays in growth and stress axis maturation in F1 generations fish, and these effects persist in the F2 generation. The developmental profiles of key genes of the somatotropic and HPI axes were altered by BPA, along with whole body composition, suggesting that BPA exposure leads to a metabolic disturbance in fish, resulting in reduced growth. Additionally, the altered plasma cortisol response to acute stress in F1 and F2 juveniles provides evidence for multigenerational effects of BPA on stress axis functioning. The current study proposes that BPA-induced epigenetic modifications during early development may be playing a key role in the generational effects on growth and stress axes disruption in trout. The finding that the growth and developmental changes to BPA exposure also corresponds with endocrine and metabolome changes in multiple generations in trout is novel, and underscores the necessity to develop new risk assessments tools for chemicals that are maternally transferred in fish.

Cortisol, the principal glucocorticoid secreted from the adrenal glands, is essential for life. Healthy cortisol levels are maintained through negative feedback on the central nervous system (CNS) – pituitary stimulatory apparatus which regulates production of adrenocorticotropin (ACTH) and contains a light–entrained intrinsic CNS driven diurnal rhythm. Cortisol participates in a regulatory mechanism where inflammatory cytokines stimulate cortisol release and cortisol in turn suppresses cytokine release. The effects of cortisol in inflammatory states include elevating blood pressure and metabolic regulation. This thesis contains three exploratory studies examining circulating cortisolaemia using the best available methodologies (total and free cortisol and corticosteroid-binding globulin (CBG)) in clinical states characterized by immune activation/ inflammation and altered blood pressure. These clinical states include: (1) septic shock, (2) hypertensive disorders of pregnancy and (3) obesity-induced hypertension. Prior to the studies described here, little was know about cortisolaemia in these common pathological states. Septic shock is a life threatening condition that complicates severe infection and is characterized by systemic inflammation and refractory hypotension. High plasma total cortisol levels and attenuated responses to synthetic ACTH stimulation are associated with increased mortality. The use of corticosteroids in septic shock has been highly controversial for decades, however recent trials have reported haemodynamic and survival benefits associated with the use of physiologic steroid replacement in patients with relative adrenal insufficiency (RAI) – currently defined as a total cortisol increment of 248 nmol/L or less following ACTH (250 μg) stimulation. However, CBG and albumin levels fall by around 50% with an increase in plasma free cortisol in critical illness. Hence, total cortisol may not reflect the biologically active free (unbound) cortisol, suggesting that standard assays for plasma cortisol (which measure total plasma cortisol) underestimate HPA axis activity. In this study, we have showed that plasma free cortisol is a better guide to circulating glucocorticoid activity in systemic infection than total cortisol. We have also validated the use of Coolens’ method in estimating free cortisol in systemic infection, using plasma total cortisol and CBG measurements as plasma free cortisol is not performed in clinical laboratories. Free cortisol measurement allows better categorization of RAI and non-RAI groups with a free cortisol increment of 110 nmol/L as cut-off. Moreover, we have shown that survivors of RAI have normal adrenocortical function on follow-up testing suggesting a lack of functional adrenal reserve rather than adrenal damage during critical illness. Larger randomized controlled trials will be required to redefine RAI using free cortisol measurements and relate that to clinical outcomes and responses to corticosteroid therapy. Nitric oxide (NO) is normally produced in the endothelium by the constitutive form of the NO synthase and this physiologic production is important for blood pressure regulation and blood flow distribution. Studies have shown that an overproduction of NO by the inducible form of NO synthase (iNOS) may contribute to the hypotension, cardiodepression and vascular hyporeactivity in septic shock. Clinical studies of non-selective inhibitors of the L-arginine nitric oxide pathway showed increased mortality from cardiovascular complications. However, glucocorticoids, which improve vasopressor sensitivity, may act by partially suppressing NO synthesis through selective direct inhibition of iNOS, and suppression of inflammatory cytokine synthesis. Hence, plasma nitrate/ nitrite (NOx) levels may provide a titratable end point to individualize glucocorticoid therapy in sepsis. The NOx study in this thesis showed that cortisol (total and free), CBG and NOx correlated to illness severity. Free cortisol, and to a lesser extent total cortisol, but not NOx levels, predicted septic shock. NOx levels were characteristically stable within individuals but inter-individual differences were only partly accounted for by illness severity or renal dysfunction. NOx levels correlated weakly with cortisol, did not relate to the need for vasopressors and were not suppressed by hydrocortisone treatment. Thus, NOx is not a suitable target for glucocorticoid therapy in septic shock. Pregnancy is the only sustained physiologic state of hypercortisolism in humans. A large body of data suggests that excessive foetal and prenatal glucocorticoid exposure leads to reduced birth weight and adverse health in offspring such as elevated blood pressure and insulin resistance. Pre-eclampsia and gamete donor pregnancies are associated with immune activation, elevated inflammatory cytokines as well as elevated blood pressure. Prior to the study described in this thesis however, there was no prospective data on maternal cortisolaemia in these complicated pregnancies. My study has demonstrated for the first time that there was a substantial fall in plasma CBG levels in the last few weeks of gestation with a corresponding rise in free cortisol in normal pregnancy, a finding obscured for methodological reasons in past studies. This free cortisol elevation in late pregnancy may facilitate organ maturation in the foetus and perhaps prepare the mother for the metabolic demands of labour. In pre-eclampsia and gestational hypertension, plasma CBG, total and free cortisol levels were lower in late third trimester; and in IUGR, plasma CBG levels were suppressed from 28 weeks gestation until delivery but with no significant difference in plasma total and free cortisol. Women with assisted reproduction using donor gametes/ embryos had significantly lower plasma CBG, total and free cortisol levels even in those with normal pregnancy outcomes. Low CBG may be due to reduced synthesis or enhanced inflammation-driven degradation. Low maternal cortisol may be due to a lack of placental corticotropin-releasing hormone, or reduced maternal ACTH, driving cortisol production. This unanticipated maternal hypocortisolism in complicated pregnancies may trigger precocious activation of the foetal HPA axis and could have implications for postnatal and adult health. Speculatively, since excess prenatal GCs increase HPA axis activity, we proposed that maternal hypocortisolism may predispose to the hypocortisolaemic state characterized by fatigue, pain and stress sensitivity, in offspring. The third state of immune/ inflammatory activation associated with blood pressure dysregulation studied in this thesis is obesity. The epidemiologic relationship between obesity and hypertension is widely recognised. Central obesity in particular has been associated with exaggerated HPA responses to stimuli. Studies of severe dieting and starvation resulted in hypercortisolism and a significant decrease in CBG. The HPA axis and the renin-angiotensin-aldosterone system (RAAS) have been implicated in the pathophysiology of obesity-induced hypertension. However, there is little data on the effect of moderate weight loss (30% caloric restriction) on adrenocortical function, and the relation of adrenal hormones to altered blood pressure with weight loss. In this study, measures of HPA axis and RAAS and blood pressure monitoring were performed in twenty-five obese subjects before and after a 12-week diet program (6000kJ/day). Short-term, moderate weight loss (mean 8.5 kg) was associated with a small reduction in blood pressure (mean arterial pressure 6 mmHg) and significantly reduced levels of aldosterone and renin but not cortisol levels. These findings suggest that aldosterone may have an important role in the blood pressure reduction with weight loss via a renin mediated mechanism, perhaps involving renal sympathetic tone. In contrast to severe caloric restriction, HPA axis activation does not occur with moderate weight loss. This suggests a threshold effect of weight loss on the HPA axis where greater caloric restriction is required for HPA stimulation, or a counterbalancing of central and direct adrenal effects on HPA axis function. Overall, these three exploratory studies have provided novel data on HPA axis function in systemic infection, pregnancy and in diet-induced weight loss. Each study offers a basis for further studies of HPA axis function in these disorders. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1289330 / Thesis(Ph.D.)-- School of Medicine, 2007.

Made available in DSpace on 2015-07-22T20:49:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-07-29. Added 1 bitstream(s) on 2015-08-11T03:26:28Z : No. of bitstreams: 1 Publico-345.pdf: 1277830 bytes, checksum: 6d2949e2d33e045cfec88a295d473e41 (MD5) / Associação Fundo de Incentivo à Psicofarmacologia (AFIP) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Alguns estudos pré-clínicos têm demostrado que eventos adversos na infância e adolescência representam um fator de vulnerabilidade para o surgimento de transtornos psiquiátricos na idade adulta, e que a redução da resiliência à eventos estressantes deve desempenhar um papel importante neste fenômeno. As manipulações em animais de laboratório, como a privação materna (PM) por 24 h durante o período de hiporresposividade ao estresse (PHRE), podem ser um instrumento útil para a compreensão de como os eventos no período precoce do desenvolvimento resultam em alterações comportamentais e da atividade do eixo Hipotálamo-Pituitária-Adrenal (HPA) na idade adulta. Alguns autores têm observado que a PM, quando imposta no 3° dia de vida (antes do início) ou no 11° dia (no vale) do PHRE, resulta em padrões de atividade do eixo HPA distintos. A PM no 3° dia induz à hiperatividade do eixo, enquanto que no 11° dia, resulta na hipoatividade, alterações estas observadas em animais jovens. Assim, os principais objetivos do presente trabalho foram os de estudar como a PM afetaria a atividade do eixo HPA durante o PHRE, e verificar se essas alterações teriam conseqüências duradouras. Os resultados mostraram que os efeitos da PM na liberação de ACTH mantiveram o mesmo padrão de atividade relatado na adolescência, ou seja, hiperresponsividade no grupo submetido à PM no 3o dia de vida e hiporresponsividade no grupo submetido à mesma manipulação no 11o dia de vida. No entanto, essa alteração não se refletiu na liberação da corticosterona (CORT), pois não se observou diferença na secreção deste hormônio entre os grupos. Além disso, a PM não alterou a liberação de CORT em resposta ao Teste de supressão à Dexametasona, indicando que não houve alterações no sistema de retroalimentação negativa no nível hipofisário do eixo HPA. A PM afetou o comportamento do tipo ansioso nos animais de ambos os grupos PM, sendo que tal alteração parece não ter sido mediada por mudanças na densidade do sítio benzodiazepínico do receptor GABAA. Os resultados indicaram que, embora a PM não leve a alterações permanentes na secreção da corticosterona, este pode ser um modelo animal interessante para se estudar o substrato neurobiológico que faz com que um evento adverso durante o desenvolvimento aumente a vulnerabilidade aos transtornos relacionados à ansiedade. / Adverse events in childhood have been associated to the development of psychopathologies, such as depression and anxiety disorders. In rats, stressful events during neonatal period, like 24h Maternal Deprivation (MD), may be an interesting tool to understand how stress during early life leads to changes in behavior and stress response in adulthood. According to some studies, MD on the 3rd day (MD 3-4) or 11th day (MD 11- 12) of life results in opposite changes in the activity of the Hypothalamus-Pituitary- Adrenal (HPA) axis, i.e., hyper and hyporresponsiveness, respectively. Since in human beings psychopathologies has been related to impairment in resilience to stress the aim of this work was to investigate whether MD leads to long lasting changes in HPA axis functioning and differential behavioral features in animal models of anxiety. The results obtained indicate that only the ACTH release presented the pattern we hypothesized. Conversely the corticosterone (CORT) plasmatic levels do not reflect this pattern. Moreover, MD did not affect the CORT release in response to the Dexamethasone Suppression Test, indicating that there are MD did not alter the negative feedback system. Although MD did not lead to convincing alteration to CORT levels it did change anxiety-like behavior in the group MD 11-12. However this behavioral change did not seem to be mediated by expression of benzodiazepine site in GABAA receptors. The results indicate that even though the MD procedure does not lead to consistent changes in the peripheral component of the HPA axis it could still be an interesting animal model to study the neurobiological underpinnings of how adverse events in early life increase the vulnerability to psychopathologies. / FAPESP: 2006/06415-4 / TEDE / BV UNIFESP: Teses e dissertações